Decided I'd try something a little different on this car - on my last car (Mazda2) that I went full retard on suspension-wise... I ran tons of spring rate and no front sway bar at all. With $$ shocks they were tolerable but definitely STIFF on the street. Trying to avoid hating myself with this car so decided I'd buy some H&R front and rear 26mm sway bars. Went with them because they're solid (rather not worry about one snapping), priced decently, and according to many they use some special hotdog butter or something impregnated in their bushings and they just plain don't squeak or ever need lubed.
They sell the
28mm front and 26mm rear as a matched pair, and a 26mm front and 24mm rear as a matched pair. I ran numbers on all of them and in a nutshell the 28/26 SEEMS to be almost identical to stock as far as front/rear roll couple split goes. Since I'm not wanting to up the spring rate significantly, I DO want to get rid of some overall body roll via the front... but I want to add MORE roll stiffness to the rear to try and move the bias a bit towards oversteer to make it a little more lively. You can see the "total body roll" number in the spreadsheet snips below and how each set of bars affects it. Also the weight transfer from inside to outside tires as you change the front vs rear stiffness.
I'm running some VERY quick and dirty numbers through my spreadsheet which I used successfully in modeling the Mazda2 suspension and developing over about 6 years. It is VERY important to note that I have not verified any of these numbers myself. MANY dimensions are based on David's numbers alone. At SOME point I intend to get my car in the garage while it is still 100% stock geometry-wise and plot everything out with lasers and plumb bobs, etc. for higher accuracy.
As noted in the spreadsheet - when numbers go negative certain stuff needs to be taken with a grain of salt. Also something the spreadsheet does NOT take into account is fore-aft G-loading in a turn (braking/accel). So even if you have one setup with heavy springs, the other with heavy sway bars and soft springs, both can show identical dynamic corner loading... but the difference is that the softer springs car will squat a lot more on accel potentially picking up the inside front tire. I don't suspect that this is near as high a priority as it was for my Mazda2 which had an open diff.
Also I need to noodle on how to calculate the track width - on here I'm using center of contact patch to center of contact patch, but that isn't where the car technically pivots if it goes 2 wheels up. In the grand scheme of things it doesn't matter... the number changes are all relative to each other and just like a dyno should be treated as a tool to utilize, not an end all be all "this is exactly correct" type thing.
I will almost for sure install the rear first alone out of sheer laziness and lack of time. I'd like to try and get some data on rear only vs front + rear at VIR... but trips there are $$$. I may actually do an autocross in a couple weeks with the rear bar only, and try to do another after installing the front bar as well. Won't be scientific, but if I'm completely honest... on track it's moreso to keep the tires from rolling over as much to extend their life.
Stock suspension:
View attachment 257888
Stock front bar, 26mm rear bar:
View attachment 257887
26mm front bar, 26mm rear bar:
View attachment 257886
28mm front bar, 26mm rear bar:
View attachment 257884
